the string (between . and !) i need to filter contains numbers and chars - regular content only has numbers.

If uBlock understands regex's, you'll do better to rework your expression anyway. I think the / has to be escaped and .* means anything. .*.* therefore also means anything. If you want the "." you'll need to escape it so "/*.*.*" becomes "\/*\..*\..*". Great stuff

However it's always better to point out the page where there is an issue along with what is the issue, sometimes the solution is elsewhere than where you might think. In the current case, I visited the site rp-online.de, and I am guessing the issue is these ugly ads which appears as a result of using a blocker. If you are willing to install the dev version of uBlock Origin (available on AMO), then these anti-adblock ads can be dealt with more simply with the following filter (it's a new kind of filter):

rp-online.de##script:contains(uabInject)

This will disable the specific inline script tag which is responsible for the self-defacement behavior of the site.